The traditional melt-quench technique was used to synthesize non-oxide (Ga2Ge)100-x(Ga3Sb2)x
(x = 15, 30, 45, 60) glass alloys. The vacuum thermal evaporation unit was used to obtain thin films of prepared sample for investigation of optical properties. SEM, XRD and DSC technique were used to find the thermal and structural properties of the materials. The linear properties like optical bandgap, extinction coefficient for prepared samples have been studied in present paper of Ge-Ga-Sb for application of optoelectronics. The impurities present in the prepared thin films were defined by FTIR transmittance spectra. The extinction coefficient (k) value decreases with increase in Sb concentration while absorption coefficient (α). It was noticed that value of energy bandgap (Eg) derived from Tauc’s plot varies from 2.9 eV to 1.25 eV. Urbach energy is inversely proportional to the bandgap of the materials. As the Sb concentration increases the band gap goes on decreases which result the increase in Urbach energy. Mott and Davis model has been used for explaining decrease in energy gap of prepared glassy alloys.